Semiconductor dice are used in the construction of electronic components, such as multi chip modules. For example, bare semiconductor dice can be mounted to substrates formed of ceramic and FR-4 materials. Flip chip mounting of bumped dice is one method for electrically connecting the dice to the substrates. With flip chip mounting, solder bumps on the device bond pads are reflowed into electrical contact with contacts on the substrate. Chip on board (COB) mounting of dice to substrates can also be employed. With chip on board mounting, wire bonds are formed between the device bond pads and contacts on the substrate. TAB mounting is another mounting method. With TAB mounting, electrical connections are made to the device bond pads, using a multi layer tape comprising a polymer backing with patterns of conductors.
Chip scale packages are sometimes used in place of bare dice for fabricating electronic components. Typically, a chip scale package includes a substrate bonded to the face of a bare die. The substrate includes the external contacts for making outside electrical connections to the chip scale package. The substrate for a chip scale package can comprise a flexible material, such as a polymer tape, or a rigid material, such as silicon, ceramic, glass or FR-4. The external contacts for one type of chip scale package include solder balls arranged in a dense array, such as a ball grid array (BGA), or a fine ball grid array (FBGA). In general, chip scale packages can be mounted to substrates using the same mounting methods employed with bare dice (e.g., flip chip, COB, TAB).
Besides making permanent electrical connections to bare dice and chip scale packages for fabricating electronic components, electrical connections are sometimes necessary for testing applications. For example, bare dice are tested in the manufacture of known good die (KGD). Chip scale packages must also be tested prior to use in electronic components. In these cases the electrical connections with the device bond pads for bare dice, or with external contacts for chip scale packages, are preferably non-bonded, temporary electrical connections. In addition to being temporary, the electrical connections must have a low contact resistance, and preferably cause minimal damage to the device bond pads or external contacts.
The present invention is directed to an improved interconnect for making electrical connections with semiconductor components including dice and chip scale packages.